The rotary cylinder barrels of axial piston hydraulic pumps or motors are commonly made of cast iron or steel to withstand the forces generated in today's high pressure units. The pistons of such units are normally made of steel and many of such cylinder barrels use cylinder bore liners made of a metal different from the remainder of the rest of the barrel to prevent piston galling and seizure during operation.
Heretofore, the cylinder liners have typically been made from a metal such as bronze or a bronze alloy. The method of making those cylinder barrels generally included machining oversized bores within the barrel and either mechanically, chemically or metallurgically bonding the cylinder liners within the bores. The size relationship of the bore and the bore liner is extremely critical thereby requiring precision machining processes to ensure proper fit up. Such precision machining adds significantly to the overall cost of making the cylinder barrel. Additionally, such bronze liners are inherently softer than the steel pistons which reciprocate therein and are somewhat prone to wear and scuffing.
In view of the above, it would be desirable to have a cylinder barrel which is more economical to manufacture and in which the bore liners are made from a nonmetallic material which is more resistant to wear and scuffing than the heretofore known metal bore liners.
The present invention is directed to overcoming one or more of the problems as discussed above.